Axially and radially adjustable lantern

ABSTRACT

A portable handheld searchlight for providing a high-intensity beam of electromagnetic radiation for comparatively long periods of time from a self-contained, easily portable power source. A Xenon gas discharge lamp is utilized as the source of electromagnetic radiation in the searchlight and it is reflected therefrom by a conventional parabolic reflector. Mechanical adjustments are provided for moving the Xenon lamp along the axis of the parabolic reflector to points closer thereto and further therefrom than a focal point of the parabolic reflector to vary the dispersion or divergence of the reflected beam. A radial adjustment for positioning the Xenon lamp along the axis, which adjustment is generally only made once at the time of manufacture, may also be provided. A light shield comprising a cylindrical tubing around the Xenon lamp is also incorporated as part of the structure to intercept the electromagnetic radiation emitted from the lamp that has not been reflected from the reflector and allows transmission thereof only in directions substantially parallel to the axis of the reflector. A complete electrical power supply system including a battery for providing electrical energy, and circuitry for providing the functions of comparatively high voltage for starting or igniting the gas discharge lamp and intermediate parallels of electrical energy to the lamp after ignition but prior to steady state operation, and also electrical energy of a comparatively low voltage for sustained steady state operation.

, nited States Patent [151 3,648,045

Le Vantine et a1. 5 Mar. 7, 1972 [54] AXIALLY AND RADIALLY Primary Examiner-Samuel S. Matthews ADJUSTABLE LANTERN Assistant Examiner-4W. L. Gellner A t -D Fink [72] Inventors: Allan D. Le Vantine, 18225 Rancho St.; tome), onB elstem Glen D. Benskin, 18233 Rancho St., both of Tarzana, Calif. 91356 [57] ABSTRACT A portable handheld searchlight for providing a high-intensity [22] filed 1969 beam of electromagnetic radiation for comparatively long [21] App1.No.: 818,654 periods of time from a self-contained, easily portable power source. A Xenon gas discharge lamp is utilized as the source of electromagnetic radiation in the searchlight and it is reflected therefrom by a conventional parabolic reflector. Mechanical [58] Fieid H 4 44 2 adjustments are provided for moving the Xenon lamp along the axis of the parabolic reflector to points closer thereto and further therefrom than a focal point of the parabolic reflector [56] References cued to vary the dispersion or divergence of the reflected beam. A UNITED STATES PATENTS radial adjustment for positioning the Xenon lamp along the axis, which adjustment is generally only made once at the time of manufacture, may also be provided. A light shield comprising a cylindrical tubing around the Xenon lamp is also incorporated as part of the structure to intercept the electromagnetic radiation emitted from the lamp that has not been reflected from the reflector and allows transmission thereof only in directions substantially parallel to the axis of the reflector. A complete electrical power supply system including a battery for providing electrical energy, and circuitry for providing the functions of comparatively high voltage for starting or igniting the gas discharge lamp and intermediate parallels of electrical energy to the lamp after ignition but FOREIGN PATENTS OR APPLICATIONS prior to steady state operation, and also electrical energy of a comparatively low voltage for sustained steady state opera- 1,033,545 4/1953 France ..240/44.2 1,020,934 2/ 1966 Great Britain ..240/44.2

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Patented March 7, 1972 3,648,045

6 Sheets-Sheet 1 I IIVVAW 7085' 5.4 [N QBMJKM/ ALLA/v 0. LE VANTINE (aw M Patented March 7, 1972 3,648,045

6 Sheets-Sheet 13 lNVEA/TOES GLEN DBMS/ml 4Q ALLAN 0 L: VANT/NE Patented March 7, 1972 6 Sheets-Sheet I;

. AXIALLY AND RADIALLY ADJUSTABLE LANTERN BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to the searchlight art and more particularly to an improved, portable, handheld Searchlight arrangement.

2. Description of the Prior Art In many applications it is desired to have a portable, handheld, high-intensity, electromagnetic radiation emission device for providing illumination of a particular area with electromagnetic radiation. It will be appreciated that such electromagnetic radiation may be in the visual portion of the electromagnetic radiation spectrum for direct observation, it may be in the infrared portion of the electromagnetic radiation spectrum for utilization with so-called infrared scopes or other infrared scanning or picture imaging devices. Such applications, of course, include policework, surveillancework, military utilizations for both battle field as well as reconnaissance, sportsmen including hunters, hikers, campers, and the like, search and rescue operations and many other types of activities.

In such portable Searchlight arrangements, whether in the visual or infrared portions of the electromagnetic radiation spectrum, the unit should have certain performance characteristics in addition to the intensity of the light emitted. That is, it is preferably comparatively light weight so that it may be portable and handheld during operation, including its selfcontained power source, and also that it have a variable field of illumination capability so that a comparatively narrow area may be brightly illuminated or a comparatively wide area illuminated to a lesser degree of brilliance.

To the best of applicants knowledge no prior art types of portable illumination devices have been able to provide the desiderata. That is, flashlights and the like utilizing heated filaments sources of electromagnetic radiation have generally such poor'efficiency characteristics that the light intensity per unit weight particularly per unit weight of power source is comparatively low. Lasers, on the other hand, while providing a high-intensity light beam require comparatively large power sources for generating the laser beam as well as being comparatively expensive.

Gas discharge lamps together with appropriate reflecting surfaces, can provide the comparatively high intensity desired but to the best of applicants knowledge no such discharge lamp has been incorporated into a system with a portable electric power supply therefor providing the different levels of electrical energy needed by the gas discharge lamp for successful operation.

BRIEF DESCRIPTION OF THE INVENTION Accordingly, it is an object of applicants invention herein to provide an improved portable searchlight arrangement.

It is another object of applicants invention herein to provide a a portable, handheld searchlight arrangement with a self-contained power supply and circuitry therefor.

It is yet another object of applicants invention to provide an improved high-intensity, portable, handheld searchlight.

The above and other objects of applicants invention are achieved, according to one aspect thereof, by providing a case means in which the structure for generating the beam of electromagnetic radiation is mounted. A suitable parabolic reflector is mounted in the case means and the parabolic reflector has, in common with such conventional parabolic reflectors, an axis having at least one focal point thereof in close proximity to the reflector. The source of electromagnetic radiation, in this embodiment of applicants invention, is a gas discharge Xenon lamp which is mounted on the axis of the reflector. To allow accurate positioning of the reflector, this embodiment of applicants invention incorporates both radial adjustment means and axial adjustment means. The radial adjustment means allows movement of the Xenon lamp in radial directions from the axis of the parabolic reflector. The radial adjustment is generally utilized only once for an initial factory setting to allow precise alignment of the Xenon lamp on the axis of the parabolic reflector.

An axial adjustment means is also provided for moving the Xenon lamp to positions closer to the reflector and further from the reflector by the preferred focal point thereof as well as allowing positioning of the Xenon lamp directly on the focal point. It is conventional to allow positioning of the course of electromagnetic radiation directly on the focal point so that all the electromagnetic radiation emanating from the reflector is generally in directions parallel to the axis thereof. Whenthe lamp is positioned off the focal point, but still on the axis of the reflector, the illumination emitted by the reflector is still substantially symmetrical about the axis but will not be sub stantially parallel to the axis thereof. That is, some illumination will'be allowed to diverge from the reflector to allow a wider area of illumination though at less intensity. It will be appreciated that comparatively small movements along the axis of the reflector by the source of electromagnetic radiation from the focal point can provide comparatively large angular dispersions.

In order to provide more precise control of the emitted beam, applicants prefer to include a light shield comprising a cylindrical tube around the source of electromagnetic radiation. The light shield intercepts the electromagnetic radiation emitted by the bulb that was not reflected by the reflector and thus prevents the comparatively wide angular dispersion thereof and permits only electromagnetic radiation in the desired path substantially parallel to the axis of the reflector.

The preferred form of applicants invention also includes a portable source of electric energy such as a battery together with circuitry necessary for operation of the electromagnetic radiation emission device. When a Xenon lamp or other gas discharge lamp is utilized as the source of electromagnetic radiation such as electromagnetic radiation in the visual portion of the electromagnetic radiation spectrum, then the circuitry must include not only the necessary elements for supplying different levels of electrical energy but also a means for switching from one level to the other as necessary for operation. That is, there may be considered to be four separate levels of electrical energy necessary for complete operation and the appropriate switching arrangements therebetween. When the Xenon lamp is first started it requires the first level of electrical energy comprising a comparatively high voltage in order to ionize the gas between the electrodes of the lamp to establish conduction therebetween. Applicant prefers that this be an alternating current signal.

There is next included a first source of DC electrical energy comprising the second level of electrical energy having a comparatively high-voltage value utilized to sustain the are between the electrodes through the gas that has been established by the AC signal.

The high DC voltage may be decreased to an intermediate direct current voltage level comprising the third level of electrical energy that provides sufficient power dissipation in the arc to initially heat the cathode of the source of electromagnetic radiation so that the electric emission is sufficient to establish a high-enough current density for maintaining the arc. The fourth level of electrical energy comprises a comparatively low-voltage direct current, which is the normal operating voltage, is applied to maintain satisfactory operation of the gas discharge lamp under the stable operating conditions therefrom; appropriate switching between the four different electrical energy requirements is also provided.

In various embodiments of applicants invention described herein, different methods for generating the four different electrical energy requirements and for switching therebetween are shown and in each the fundamental source of electrical energy has a voltage rating equivalent to the lowest or the steady state DC operating voltage requirement for the lamp.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of one embodiment of applicants invention herein;

FIG. 2 is a section view along the line 22 of FIG. 1;

FIG. 3 illustrates another axial adjustment arrangement useful in the practice of applicants invention herein;

FIG, 4 is an end view of the embodiment of applicants invention shown in FIG. 1;

FIG. 5 illustrates, in schematic diagram form, a circuit useful in the practice of applicants invention herein;

FIG. 6 illustrates, in schematic diagram form, another circuit useful in the practice of applicants invention herein;

FIG. 7 illustrates, in schematic diagram form, another circuit useful in the practice of applicants invention herein;

FIG. 8 illustrates, in schematic diagram form, another circuit useful in the practice of applicants invention herein; and

FIG. 9 illustrates, in block diagram form, the circuitry useful in applicants invention;

FIGv 10 illustrates, in schematic diagram form, another circuit useful in the practice of applicants invention; and

FIG. 11 illustrates, in schematic diagram form, another circuit useful in the practice of applicants invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Before detailing a description of applicants invention herein, applicants wish to point out that the specific structure selected for utilization in the description of the preferred embodiments to illustrate the best mode known to the applicants of taking advantage of equivalent structures for performing the same or substantially identical functions. Similarly, while applicants illustrate their invention as practiced with a Xenon gas discharge lamp, it will be appreciated that other sources of electromagnetic radiation including those in the visual, ultraviolet or infrared portions of the spectrum may be desired, and can equally well be utilized in applicants invention herein. Further, applicants have selected for inclusion in this description a source of electrical energy in the 12 to l4-volt DC range since this is a conventional and readily available battery. However, it will be appreciated, many other voltage ranges for the source of electrical energy may be selected depending upon the particular application.

The Xenon lamp referred to above as the source of electromagnetic radiation does, of course, put out a high degree of visual electromagnetic radiation as well as electromagnetic radiation in the infrared portion of the electromagnetic radiation spectrum. Accordingly, it is desired to use a Xenon lamp to provide infrared radiation without visual radiation such as may be required in some military operations and suitable filters may be placed over the end of the lamp to eliminate the transmission of visual electromagnetic radiation. Similarly, in those applications of only ultraviolet light may be desired, such as those applications where fluorescence of various minerals is to be detected, either a suitable ultraviolet emitting source of electromagnetic radiation may be utilized and/or additional filters for eliminating visual or other bandwidths of electromagnetic radiation may be incorporated.

Referring now to FIGS. 1, 2 and 4, there is illustrated a preferred form of applicants invention of an improved portable searchlight generally designated 10. As shown thereon, there is provided a case means 12 in which there is mounted a source of electromagnetic radiation 14. The source of electromagnetic radiation 14 is adapted to emit an electromagnetic radiation having energy in a preselected bandwidth. With the definition of the above-mentioned criteria, the source of electromagnetic radiation 14 may, for purposes of example, be considered a Xenon gas discharge lamp. As such the Xenon lamp l4 emits electromagnetic radiation having energy in both the visual bandwidth portions of electromagnet radiation spectrum and also the infrared portion of the electromagnetic radiation spectrum. A lens 16 may be mounted on the case means 12 through a lens is not necessary for proper operation of many embodiments of applicants invention. If the lens means 16 is included it may be a band-pass filter-type lens in which, for example, only infrared electromagnetic radiation is transmitted therethrough and visual energy is stopped from transmission therethrough. Alternatively, the lens means 16 may transmit electromagnetic radiation in the visual portion of electromagnetic radiation spectrum, Thus, the lens means 16 may have any desired transmission characteristics as required for particular applications.

A reflector means 18 is mounted inside the case means 12 and it receives a first portion of electromagnetic radiation emitted the the source of electromagnetic radiation 14. The first portion of electromagnetic radiation received by the reflector 18 is generally designated by the arrow 20 and after striking the reflector means 18 it is reflected therefrom in a direction indicated by the arrow 22 which, for the preferred embodiment of applicants invention wherein the reflector means 18 is a parabolic reflector, the first preselected direction of distribution pattern indicated by the arrow 22 is parallel to the axis of the generally parabolic reflector means 18. Such electromagnetic radiation passes through the lens means 16, if such is included, to the extent of the transmission characteristics thereof, to regions external the portable searchlight 10.

A second portion of the electromagnetic radiation emitted from the electromagnetic radiation source 14 is designated by the arrow 24 and this portion of electromagnetic radiation 24 is not intercepted by the reflector 18 because ofthe geometric relationship therebetween. However, in order to concentrate electromagnetic radiation emitted by the portable search light 10 into a desired columnated beam applicants prefer to include a shield means 26 that intercepts such second portion of electromagnetic radiation 24 to prevent it from a comparatively wide dispersion or distribution pattern and substantially allow only the transmission of electromagnetic radiation in a direction indicated by the arrow 22.

A mounting means 28 comprising a flat-mounting portion 30 and a rear-mounting portion 32 is provided for retaining the source of electromagnetic radiation 14 in a particular, variable, position with respect to the parabolic reflector means 18. An adjustment means 34 is provided as cooperatively coacting with the mounting means 28 to allow moving the source of electromagnetic radiation 14 into a plurality of positions with respect to the reflector means 18.

A handle means 36 is coupled to the case means 12 to allow convenient carrying the portable searchlight l0 and, if desired, the handle means 36 may include therein the electrical circuitry generally indicated at 38 interior the handle means 36 as well as a source of electrical energy generally indicated at 40 which also may be included within the handle means 36, as described below in greater detail.

As shown more clearly on FIG. 2, the reflector means 18 which, as noted above, in the preferred embodiment of applicants invention, is a parabolic reflector, has an axis 42 and at least one focal point of the parabolic reflector 18 is at the point indicated at 44. When the source of electromagnetic radiation 14 is positioned exactly at the focal point 44 light reflected therefrom as indicated by the portion of electromagnetic radiation at the arrow 20 strikes and parabolic reflector 18 and is reflected therefrom in the direction indicated by the arrow 22 which is parallel to the axis 42. Thus a searchlight effect is provided by the reflector 18. The electromagnetic radiation in a second portion 24 emitted from the source of electromagnetic radiation 14 strikes the light shield means 26 and is prevented from being emitted from the portable searchlight 12 at comparatively wide angular dispersion patterns from the desired direction parallel to the axis 42. However, in some embodiments of applicants invention it may be desired to have a divergence to the light emitted from the portable searchlight 10 such that it is not all concentrated substantially in directions parallel to the axis 42 as indicated by the arrow 22. In those embodiments of applicants invention an axial adjustment means as indicated by the rear adjustment means 34 is provided to move the source of electromagnetic radiation 14 along the axis 42 to positions closer to the reflector 18 than the focal point 44 and further from the reflector 18 than the focal point 44 on the axis 42. This, of course, changes the reflective characteristics of the light source 14reflector means 18 combination-such that the electromagnetic radiation reflected by the reflector means 18 will not be substantially parallel to the axis 42. Thus, at a given distance from the portable searchlight at maximum intensity the light source 14 is at the focal point 44 and the electromagnetic radiation is substantially parallel to the axis 42. By moving the light source 14 along the axis 42 but away from the focal point 44 an angular dispersion in a preferred and preselected angular pattern distribution is obtained so that a greater area is covered by the light emitted from the portable Searchlight l0 and, consequently, at a lower intensity per unit area thereof. The axial adjustment is obtained by rotating the knob 46 which is retained by retainer ring 48 mounted on the case means 12 at the near 50 thereof. The adjustment knob 46 threadingly engages a dielectric screw means 52 that is coupled to the rear mounting means 32 which, in this embodiment of applicants invention, is in the form of a tubular friction clip 54 in which the'dielectricscrew means 52 is coupled by a screw 56 at the rear end 58 thereof and a rear contact 60 of the source of electromagnetic radiation 14 is held tightly at a forward end 62 of the friction clip 54 by screw 199. Thus, rotation of the knob 46 moves the dielectric screw 52 along the axis 42 in the directions indicated by the double-ended arrow 64 to move the center of the source of electromagnetic radiation 14 to positions closer to or further away from the reflector 18 than the focal point 44. The forward contact 66 of the source of electromagnetic radiation 14 is frictionally retained for axial sliding movement therein by the forward-mounting means 30, described below in greater detail.

It will be appreciated that a level operation could equally well be provided for the axial movement of the source of electromagnetic radiation 14. One such embodiment of applicants invention generally designated 70 is shown in FIG. 3 wherein there is provided a case means 12 which may be generally similar to the case means 12 shown in FIG. 1 in which a rear-mounting means 72 is provided for axial adjustment ofa source of electromagnetic radiation 74 along an axis 76 of a generally parabolic reflector means 78 which may be similar to the parabolic reflector 18 shown in FIG. 1. A clip 80 which may be similar to the clip 54 shown in FIG. 2 is provided for frictionally engaging a rear contact 82 of the source of the electromagnetic radiation 74. A dielectric rod means 84 is retained by screw means 86 on the rear portion 88 of the clip 80 and is mounted by pin means 90 in a lever 92. The lever 92 projects from the case means 12' and has a handle portion 94 which may be moved in the directions indicated by the double-ended arrow 96 to move the source of electromagnetic radiation 74 in the directions indicated by the doubleended arrow 98. The lever means 92 is pivoted on the bracket 100 by pivot pin means 102. The handle 94 is guidedin a slot 106 of a guide means 108 that is coupled to a case means extension 110. Screw means 201 is provided to provide the same functions as screw means 199 shown on FIG. 2 and as described above. It will be appreciated that many variations of the lever adjustment means for providing axial movement of the source of electromagnetic radiation as indicated in FIG. 3 or the rotary means for providing the axial movement of the source of electromagnetic radiation 14 may be provided to achieve the desired functional result within applicants invention of axial positioning of the source of electromagnetic radiation in desired locations with respect to the reflector means 18.

In the preferred embodiment of applicants invention the spring clip 32 is electrically conductive and an electrical lead 112 that is connected to the electrical circuit 38 supplies electrical energy by the connection at screw means 56 to the clip 32 to make electrical contact with the rear contact portion 60 of the source of electromagnetic radiation 14. A conventional lamp lead means 114 may be provided on the'sourceofelectromagnetic radiation 14 and if so it may be suitably electrically connected to the clip 54 as desired. However, in the preferred embodiment of applicants-iinvention, electrical connection to the source of electromagnetic radiation through the rear mounting means 32 is provided by the electrically conductive clip 54.

The parabolic reflector 18 has walls 116 defining an aperture 118 therethrough in axial regions thereof to allow the insertion of the rear-mounting means 32. A dielectric shield means 120 may be included to prevent arcing to the case means 12 from the clip 54.

Similarly, in the pivotal axial adjustment arrangement shown on FIG. 3 a planer dielectric shield 122 may be utilized for the same purpose.

The adjustment means 28 includes the forward adjustment means 30. The forward adjustment means 30 provides for a radial alignment of the source of electromagnetic radiation 14 is generally only utilized once as a factory setting to align the source of electromagnetic radiation 14 properlyon the axis 42 of the parabolic reflector 18. That is, off-axis alignment of the source of electromagnetic radiation 14 would result in a nonsymmetrical pattern of electromagnetic radiation emission from the portable searchlight 10. Since this is generally not desired, the radial adjustment provided by the forward mounting arrangement 30 may be utilized to position the electromagnetic radiation source 14 properly. This is shown more clearly in FIG. 4 which is a front view of the embodiment of applicants invention shown in FIGS. 1 and 2. The radial adjustment means comprising the forward mounting means 30 has a spring mounted leg mounted by spring means 132 on the case means 12. A shoe portion 130' thereof is coupled by screw 135 to the case means 12 to provide electrical and thermal conduction paths from the source 14 to the case means 12.

A pair of screw-mounted legs 134 and 136 which, as shown, may be similar, are supported by fixed shoe portions 134 and 136, respectively, and by adjustment screw means 138 and 140, respectively. Movement of the adjustment screw means 138 and 140 moves the source of electromagnetic radiation 140 generally in a plane perpendicular the axis 42. It will be appreciated that the required alignment movements are generally small and thus though the source of electromagnetic radiation 14 generally pivots about the rear contact 60 maintained in the rear spring clip 54 it is generally in such a plane perpendicular to the axis 42 until it is aligned thereon.

As shown in FIG. 4 the two screw-mounted leg means 134 and 136 generally come together to form a forward spring clip means 142 for supporting frictionally the forward contact 66 of the source of electromagnetic radiation 14. The spring clip 42 thus formed frictionally engages the contact 66 but allows axial movement of the forward contact 66 therein during axial adjustment of the electromagnetic radiation source 14. It will be appreciated that one or all of the legs 130, 134 or 136 may be made electrically conductive and the forward contact 66 may, for example, be provided as the ground connection for electrical continuity, as described below. If not, an appropriate contact lead may be suitably utilized as desired from the forward contact 66.

A rim means is shown on FIG. 2 for supporting the lens means 16. The rim means 150 and lens 16 are attached by a plurality of screws 152 to the case means 12.

As can be seen from FIG. 2 the light source means 26 generally comprises a cylindrical, tubular member of an opaque material to prevent the transmission of any electromagnetic radiation in the second portion 24 therethrough. The cylindrical light shield means 26 is generally coaxially mounted with the axis 42 of the parabolic reflector 18.

In the preferred embodimentof applicants invention, the leg means 134 and 136 for the radial adjustment 130 are substantially 120 apart as applicants have found that this provides a good adjustment on the radial movement of the source of electromagnetic radiation 14.

As noted above, the preferred embodiment of applicants invention includes a complete source of electrical energy and appropriate circuitry for starting and operating the source of electromagnetic radiation 14. It will be appreciated that many sources of providing such electrical energy have heretofore been utilized in the past but, in general, have not proven satisfactory because of inability to utilize for all functions and the portable source of electrical energy, such as a battery, that is voltage rated for the normal operating voltage of the gas discharge lamp when such is utilized as the source of electromagnetic radiation. Applicants invention, on the other hand, allows utilization of a source of electrical energy at utilization voltage rating for normal operation of the lamp for all other functions required for proper operation of the searchlight 10.

FIG. 9 illustrates a block diagram form of the circuitry and switching necessary for operation of applicants improved portable searchlight. As shown in FIG. 9 a source of electromagnetic radiation such as the source of electromagnetic radiation 14 is powered by an appropriate electrical circuit having its own electrical energy supply. In order to establish the emission of electromagnetic radiation from the source of electromagnetic radiation 14 it is first necessary to provide a high electrical potential across the lamp from the rear contacts 60 to the front contacts 66. In this embodiment, as shown on the block diagram FIG. 9, the front contact 66 is grounded. Generally a high-voltage AC potential is utilized to provide a initial ionization of the Xenon gas between the electrodes in the source of electromagnetic radiation 14 to establish the initial arc. Thus, there is provided a high-voltage AC source 160 that is connected into the circuit by a first switch 162. After the initial arc is established switch 162 is open and switch 164 is closed to bring in a high-voltage DC power 166 to sustain the arc across the electrodes in the source of electromagnetic radiation 14. Then switch 164 is opened and switch 166 is closed to bring in an intermediate voltage level DC power 167 to provide adequate power dissipation in the arc and heating of the cathode electrode in the source of electromagnetic radiation 14 to establish a sufficient current density emission to sustain the arc. Then the switch 166 is opened and the switch 170 may be closed to bring in the low-voltage DC power 172 which is utilized for sustaining the steady state are across the lamp 14. It will be appreciated that the energy provided by the high-voltage AC source 160, high-voltage DC source 166 and intermediate voltage DC source 167 are transient in nature and the low-voltage DC source 172 is utilized for the steady state operation. It will further be appreciated that switching must be instantaneous in that each successive change of voltage must occur in a manner such that there is no interruption of power being continuously applied to the lamp. Further, it is preferred that automatic switching take place to the largest extent possible during operation of the portable searchlight according to applicants invention.

In the past electrical circuits utilized for operating gas discharge lamps have generally utilized an AC power source as a source of electrical energy. The AC was converted to DC with a voltage rating up to three times or more the voltage rating required for a steady state operation. The high-voltage AC source was generally established from the AC source utilizing a transformer to step-up the potential to the required level. The high-voltage DC was then provided by the direct voltage from the comparatively high DC voltage source operating through a conventional ballast resistor. There is a transient condition between this high-voltage DC for sustaining the initial arc and the low-voltage DC requirement that was automatically taken into account by utilizing the ballast resistor to set proper DC across the lamp. As the voltage drop across the lamp decreased the lamp current increased to the level of stable operation and thus provided automatic switching of switching functions indicated by switches 164, 166, and 170.

Applicants invention, on the other hand, utilizes a DC supply source of electrical energy such as a battery equivalent to that necessary for the low-voltage DC supplied by low-voltage DC source 172 without utilizing a comparatively highlevel DC voltage source. FIG. 5 illustrates one embodiment of an electrical circuit and source of electrical energy for utilization in the practice of applicants invention, and is generally designated 200. In this circuit the Xenon lamp is generally designated 210 and may be similar to the Xenon lamp 14 described above. The circuit is conditioned for proper operation by a momentary closing of the switch 212 in the direction indicated by the arrow 214. When the switch 212 is momentarily closed in the direction indicated by the arrow 214 it is in the reset position. The reset position is the opposite position to that illustrated on FIG. 5. In the reset position, switch 212 allows current flow to charge the capacitors 220 and 222. For the circuit shown in FIG. 5, the capacitors 220 and 222 are charged to the sum of the voltage of direct current source of electrical energy 216 and battery 218. For example, if the potential required for steady state operation of the lamp 210 is 12 volts, then DC source of electrical energy 216 may be a l2- volt battery and small battery 218 may be a 6-volt battery. In this example, then, the capacitors 220 and 222 are charged to 18-volts during the period of time that the switch 212 is in the above-described reset position. The resistor 224 acts as a current limiting resistor during this initial charging operation to prevent overloading diode 226. It will be appreciated that capacitor 222 is additionally charged through diode 226 which, after the switch 212 is moved to the run position indicated by the arrow 228 and in the position indicated on FIG. 5, prevents discharging of capacitor 222. Further, when in the run position shown capacitor 220 and 222 are connected in a series across the lamp 210.

The lamp is then started by depressing switch 230. This is depressed in the direction indicated by the arrow 231 to close the indicated contact. In this start position the capacitors 220 and 222 are connected in series with the DC source of electrical energy 216. Thus, the plus side of capacitor 222 is at a potential of four times the voltage of the source of electrical energy 216 or, for the sample shown, 48-volt DC. This, as can be seen, is applied across the lamp 210 and discharge is prevented by diodes 226, 232, and 234.

The electrical chopper 236 is activated by application of the voltage from the source of electrical voltage 216 through resistor 238. Further, the supply voltage provided by the source of DC electrical energy 216 is also applied to the primary 240 of a transformer 242 which may be an autotransformer as shown, through resistor 244. The electrical chopper 236 operating cooperatively with capacitor 246 converts the DC signal thus applied at the primary 240 of the transformer 242 to an AC which by inductive coupling of the transformer 242 primary 240 generates a high-voltage AC on the order of, for example, 20,000 volts. This high potential is impressed across the primary 248 of transformer 250 and also across spark gap 252. The spark gap 252 operates as a voltage breakdown gap and sequentially conducts and discharges capacitor 255 many times during each positive and negative phase of the alternating current signal. Each discharge across the spark gap 252 is a comparatively short duration such as waveform is equivalent to a frequency on the order of one megacycle or so. Thus a high-voltage, high-frequency signal is impressed on the primary 248 of the transformer 250 and transfers by the transformer 250 to the lamp 210 and ionization of the gas therein occurs to establish an initial arc across the electrode of the lamp 210. Once the arc is established then capacitors 220 and 222 discharge as a high-voltage DC signal across the lamp 210 to sustain this initial are.

When the switch 230 is depressed in the direction indicated by the arrow 231, battery 218 is connected in series with the source of electrical energy 216. For the values cited above, this provides a voltage of 18 volts or 1 /2 times the voltage of the nominal rating of the 12-volt source of electrical energy 216 and is impressed across the lamp 210 through resistor 254, diode 232 and resistor 256. However, there will be no current flow from the battery 218 until the potential on the lamp 210 side of the diode 232 drops below the potential on the battery 218 side thereof to allow diode 232 to become forward biased and thus conduct. This only occurs after capacitors 220 and 222 have discharged through the lamp. Then the current from the combined source of direct current electrical energy 216 and the battery 218 provide the intermediate direct voltage signal required to sustain the energy for sufficient emission current density to sustain the arc and heating of the cathode.

It will be appreciated that resistors 254 and 256 act as ballast resistors and provide a voltage drop that increases as the lamp 210 current increases. As the lamp 210 current approaches the maximum value, the voltage drop across these resistors 254 and 256 is approximately equivalent to that applied by the battery 218 and the voltage then is impressed across the lamp 210 is in substantial equivalence to the supply of voltage supplied by the source of electrical energy 216.

Then, return of the switch 230 to the position shown in FIG. removes the battery 218, electrical chopper 236 and transformer 242 from the circuitry between the source of electrical energy 216 and lamp 210 thereby transferring operation of the lamp 210 to the steady state condition from source of electrical energy 216. In this embodiment of applicants invention, the lamp may be turned off by temporarily interrupting the circuit such as by depressing momentarily switch 258.

FIG. 6 illustrates another circuit, in schematic diagram form, useful in the practice of applicants invention herein. As shown on FIG. 6 this circuit, generally designated 270 is provided with a switch 272 which is movable from the run position shown in FIG. 6 and indicated by the arrow 274 to a start position which is the opposite position as indicated by the arrow 276. The switch 272 is a make-before-break, doublepole, double-throw switch. When it is depressed through the start position as indicated by the arrow 276 the DC supply 278 which may be similar to the 12-volt supply 216 described above, is connected to the electrical chopper 280, the battery 282 and the primary 284 of the transformer 286. The chopper 280 in conjunction with the capacitor 288 converts the direct current signal applied to the primary 284 of transformer 286 to an alternating current potential and by mutual inductance and direct connection of the primary 284 to a secondary 290 of the transformer 286 a highvoltage AC signal is established across the transformer 286, as described above. Also, resonant harmonics appear as relatively high-voltage spikes across capacitor 288 superimposed on the frequency generated by the electrical chopper 280. These high-voltage spikes are rectified by diode 292 through limiting resistor 294 to charge capacitor 296 to a value sufficient to supply the required highvoltage DC as the source of high-voltage DC 166 shown in FIG. 9.

However, the charging of capacitor 296 sufficiently loads the transformer 286 so that the gain thereof is insufficient to produce a voltage potential great enough to generate an arc across the spark gap 298. But, as capacitor 296 exponentially approaches its maximum charge the load on transformer 286 is reduced and the output voltage increases until the breakdown voltage of spark gap 298 is reached and the spark gap 298 conducts. As described above in connection with the embodiment shown in FIG. 5 this provides the high-voltage AC signal to the lamp 210 through the transformer 300 which operates in a manner similar to the transformer 250 described above.

The relatively high DC voltage in capacitor 296 is then discharged across the lamp 210 to supply the transient high- DC voltage signal required.

After the capacitor 296 discharges below the voltage level established by the battery 282, together with the voltage value of the source electrical energy 278 in series therewith, diodes 302 becomes forward biased and conducts and the voltage of the source electrical energy 278 and the battery 282 are impressed across the lamp 210 through resistor 304 to provide the intermediate level DC voltage signal required as described above. The resistor 304 acts in a manner similar to a ballast resistor and as the current through the lamp 210 increases to that provided in stable operation, the voltage drop across resistor 304 increases until the voltage impressed across the lamp 210 is equal to that of the source electrical energy 278 alone. Switch 272 is then moved to the run position indicated on FIG. 6 as indicated by the arrow 274 which provides the source of the electrical energy 278 connected to the lamp 210 through limiting resistor 301 and secondary 303 of transformer 300 for stable operation. The lamp may be turned off by momentarily opening switch 272a ofthe switch 272.

It will be appreciated that with the switch 272 in the posi' tion for run as indicated in FIG. 6, the battery 282 is recharged from the source electrical energy 278 through the resistors 306 and 308 as well as the coil of the electrical chopper 280. Chopper 280 ceases operation and discontinues energizing lamp 210 through transformers 284 and 300 when switch 272 is in the run position shown in FIG. 6 because there is insufficient voltage across chopper 280 to effect the operation thereof.

FIG. 7 illustrates another embodiment of a circuit useful in the practice of applicants invention generally designated 320. In the circuit 320 it is virtually identical to the circuit shown in FIG. 6 except that it is a positively grounded circuit to eliminate the need for a special shielded wire to the front end of the lamp 14 in FIG. 1 and allow direct grounding ofthe forward end through the forward contact 66 and the forward mounting means 30. That is, the case 12 may be the ground and, for example, the forward mounting support comprising the legs 130, 134 or 136, or any of them, may be electrically conductive to provide the grounding. However, operation of this circuit 320 as shown for operation of the lamp 210 operates in the manner completely analogous to that described above in connection with the circuit 270 shown in FIG. 6.

In FIG. 8 there is shown another positively grounded circuit generally designated 330 useful in the practice of applicants invention herein. The embodiment of this circuitry 330 is virtually the same as the embodiment shown in FIGS. 6 and 7. However, in this embodiment the output of the transformer 286 has been boosted by increasing the DC potential applied to the primary 284 thereof by including the battery 282' as part of the charging voltage source. However, this drained the comparatively small ampere hour of the conventional 6-volt battery utilized as battery 282' and hence a third battery 332 which, for example, with the values of the source of electrical energy 336 being 12 volts and the value of battery 282' being 6 volts, battery 332 could be on the order of 3.6 volts.

Also, as can be seen the resistor 338 is connected to the terminal 340 of the switch 342 so that when the switch 342 is in the run position, as illustrated on FIG. 8, the operational circuit of the chopper 344 is isolated from battery 336.

FIG. 10 illustrates another embodiment of a circuit that applicants have found useful in the practice of their invention to achieve the functions of starting and operating the lamp generally designated 402 which may be similar to the lamp 14 described above. Thus, this circuit 400 provides the four functions of high-voltage AC high-voltage DC intermediate voltage DC and low-level DC and the appropriate switching automatically therebetween.

As shown on FIG. 10 the on-off switch 404 supplies the negative side 406 of a l2-volt battery 408 to the lamp circuit. As shown, then, with the switch 404 closed, 12 volts is impressed across the transistors 410 and 412, which transistors are similar but are not identical, through the primaries 414 and 416, respectively of transformer 418. The negative voltage is thus impressed on the base terminal 410a and 412a on transistors 410 and 412, respectively, through resistor 420 and the primary portion 422 of the transformer 418.

Thus, each of the transistors 410 and 412 start to conduct. However, since the characteristics of the transistors 410 and 412 are not perfectly identical, one transistor actually starts to conduct before the other and thereby resulting in an oscillatory condition of conduction between the two wherein current tends to flow alternately through the circuits of transistors 410 and 412. The inductive coupling through portion 422a with portion 414a of the primary 422 of the transformer 418 and the inductive coupling between portions 4221) and portion 416 of the primary of transformer 418 drives the base terminals, such as 410a and 412a of first one of the two transistors to conduct negative and the other transistor positive. An oscillating sequence is thus set in operation. When transistor 410 and portion 422a conduct an electromotive force is set up in 414 and 416 which drives the base 410 positive and the base of 412 negative. Thus, transistor 410 ceases to conduct and transistor 402 conducts so the current flows through portion 422b and stops flowing through portion 422a of the primary 422 of transformer 418. The inductive coupling at two portions 414 and 416 results in a reversal of this process. The oscillation thus set up in portions 422a and portions 422b are impressed upon secondary 424 of the transformer 418.

It will be appreciated that the circuitry generally designated 411 thus far described for the circuit 400 comprises an inverter portion and it will be appreciated that other transformer coupled converter circuits are applicable and could be utilized to supply the output requirements therefrom as obtained from the secondary 424.

The open circuit AC voltage of 424 is on the order of 30 volts RMS when the AC voltage across the portions 422a and 422b is l2 volts. The core of the transformer 418 and the number of windings of both the primary 422 and secondary 424 are such that the voltage across 424 will be about 2 volts RMS with a load induced current of 7 amperes in the circuit of the secondary 424.

The AC voltage of the secondary 424 is rectified by a fourdiode, full-wave rectifier bridge 426. This rectifier voltage is then superimposed upon the l2-volt source by direct connection of a negative from the battery 408 to the point 428 of the four-diode rectifier bridge 462. The sum of these voltages is then impressed across the lamp 402 through the secondary 430 of transformer 432.

The AC voltage from the secondary 424 of transformer 418 is also impressed across the primary 438 of the transformer such as another transformer 434. Mutual inductive coupling between the primary 438 and the secondary 436 of transformer 434 results in approximately 20,000 volts being developed across transformer 434 with to volts input from the secondary 424 of transformer 418. This 20,000 volts is impressed on spark gap 440 through the primary 442 of transformer 432. By inductive coupling this voltage is transferred to the secondary 430 of the transformer 432 and thus is impressed across the lamp 402.

The 20,000 volts across the lamp 402 ionizes the gas between the electrodes of the lamp and causes it to conduct. As the lamp starts to conduct the voltage of the secondary 424 of transformer 418 drops to 2 volts which, superimposed on the l2-volt supply, results in 14 volts DC being impressed across the lamp 402 and the lamp 402 continues to conduct and operate in its normal manner. Although the primary 438 of the transformer 434 is still connected to the secondary 424 of transformer 418, the output voltage of secondary 424 is only 2 volts. This 2 volts is not sufficient to result in a highvoltage output from transformer 434. Thus, spark gap 440 does not conduct and, to all intents and purposes, the output circuit of 434 is open resulting in high-AC impedance across the primary 436 of transformer 434. Therefore transformer 434 does not load the secondary 424 of transformer 418.

The lamp may be turned off merely by opening the circuit here at switch 404.

FIG. 11 illustrates yet another circuit generally designated 500 that is similar in operation to the circuitry shown in FIG. 10. However, in the embodiment of the circuit 500 shown on FIG. 11, there is provided structure similar to the embodiment of applicants invention shown in FIG. 8, and in which the circuit is made operable by closing switch '510. An electrical chopper 502 operated through start switch 504 is utilized to provide the AC from the DC source as applicable here in the starting of the circuit designated 500 in a manner similar to that described. After the initial start of the lamp 506 has been obtained, the start switch 504 is released and the electrical chopper 502 is cut out of the circuit and the inverter stage generally designated 508 which is similar to the inverter stage 411 described above in the embodiment of applicants invention shown in FIG. 10 is utilized to supply the other electrical power requirements during transition and operation of the lamp 506 in a manner identical to that described above for the circuit 400. The lamp 506 is turned off by opening switch 510.

This concludes the description of applicants invention and improved portable handheld searchlight arrangement. As can be seen from the above description and the accompanying drawings, applicants have provided a conveniently portable, lightweight, searchlight that uniquely operates all functions of a gas discharge lamp with a voltage source included therein that is individually no greater than the voltage required for steady state operation.

What is claimed is new and desired to be secured by Letters Patent of the United States is:

1. An improved portable searchlight arrangement comprising, in combination:

a case means; a source of electromagnetic radiation having a forward electrode and a rear electrode spaced from said forward electrode for emitting electromagnetic radiation in a preselected distribution, and said emitted electromagnetic radiation having energy in a preselected bandwidth; reflector means coupled to said case means for support therein in a predetermined position, and comprising a parabolic reflector means having a predetermined focal point on a preselected axis thereof, and adjacent said source of electromagnetic radiation for receiving a first portion of said electromagnetic radiation in said preselected distribution and reflecting said first portion of said electromagnetic radiation therefrom in a first preselected directional pattern; mounting means for supporting said source of electromagnetic radiation at preselected positions in spaced apart relationship to said reflector means, and said predetermined focal point comprising one of said preselected positions, and said mounting means comprising: an electrically conductive forward spring clip means coupled in electrically conductive contact with said forward electrode of said source of electromagnetic radiation for sliding, frictional retention of said source of electromagnetic radiation for the condition of movement of said source of electromagnetic radiation in first portions of said preselected positions; and

an electrically conductive rear clip means coupled in electrically conductive contact with said rear electrode of said source ofelectromagnetic radiation; shield means adjacent said source of electromagnetic radiation for intercepting a second portion of said electromagnetic radiation in said preselected distribution to prevent said second portion of electromagnetic radiation from emission in a second preselected directional pattern different from said first preselected directional pattern; adjustment means on said mounting means for moving said source of electromagnetic radiation into said preselected positions, and said adjustment means comprising: axial movement means for selectively moving said source of electromagnetic radiation along said axis relative to said shield means and said reflector means to first axial positions closer to and further from said reflector means and said focal point thereof, and said first axial positions comprise said first portion of said preselected positions;

a radial adjustment means coupled to said forward spring clip means and moveably mounted on said case means;

electrically insulating means coupled to said rear clip means; and

said axial movement means coupled to said electrically insulating means;

shield support means for supporting said shield means for movement with said source of electromagnetic radiation for the condition of movement of said source of electromagnetic radiation in second portions of said preselected positions, and said source of electromagnetic radiation moveable with respect to said shield means for movement of said source of electromagnetic radiation in said first portions of said preselected positions;

energizing means connected to said forward spring clip means and to said rear clip means for supplying energy to said source of electromagnetic radiation.

; 2. The arrangement defined in claim 1 wherein:

said electrically insulating means comprises an electrically insulating screw member and said axial movement means comprises a threaded knob mounted on said case means and threadingly engaging said threaded electrically insulating means whereby rotation of said knob moves said electrically insulating means and said source of electromagnetic radiation along the axis of said reflector.

3. The arrangement defined in claim 1 wherein: said electrically insulating means comprises an electrically insulated bracket member; and

said axial movement means comprises a lever means having a pivot end and a movement end and said electrically insulating bracket means is pivotally coupled to said axial movement lever means intermediate said pivot end and said adjustment end, and said pivot end is pivotally mounted on said case means, whereby movement of said adjustment end of said axial adjustment lever moves said source of electromagnetic radiation along said axis of said reflector.

4. The arrangement defined in claim 1 wherein: said axial adjustment means comprises three strut members extending from said front spring clip means to said case means, a first and a second of said strut members adjustably coupled to said case means and the third strut member spring-mounted on said case means.

5. An improved portable searchlight arrangement comprising, in combination:

a source of electromagnetic radiation comprising a gas discharge lamp means having a forward electrode and a rear electrode spaced from said forward electrode for emitting electromagnetic radiation in a preselected distribution, and said emitted electromagnetic radiation having energy in a preselected bandwidth, and said preselected bandwidth of electromagnetic radiation is in the visible portion of the electromagnetic radiation spectrum; reflector means adjacent said source of electromagnetic radiation for receiving a first portion of said electromagnetic radiation in said preselected distribution and reflecting said first portion of said electromagnetic radiation therefrom in a first preselected directional pattern; mounting means for supporting said source of electromagnetic radiation at preselected positions in spaced apart relationship to said reflector means, and said mounting means comprising: an electrically conductive forward clip means coupled in electrically conductive contact with said forward electrode of said source of electromagnetic radiation; and

an electrically conductive rear clip means coupled in electrically conductive contact with said rear electrode of said source of electromagnetic radiation; and

at least one of said forward clip means and said rear clip means comprises a spring clip means for sliding, frictional retention of said source of electromagnetic radiation for the condition of movement of said source of electromagnetic radiation in first portions of said preselected positions; adjustment means on said mounting means for moving said source of electromagnetic radiation into said preselected positions;

shield means adjacent said source of electromagnetic radiation for intercepting a second portion of said electromagnetic radiation in said preselected distribution to prevent said second portion of electromagnetic radiation from emission in a second preselected directional pattern different from said first preselected directional pattern;

shield support means for supporting said shield means for movement with said source of electromagnetic radiation for the condition of movement of said source of electromagnetic radiation in second portions of said preselected positions and said source of electromagnetic radiation moveable with respect to said shield means for movement of said source of electromagnetic radiation in said first portion of said preselected positions; and

energizing means connected to said forward clip means and to said rear clip means for supplying energy to said source of electromagnetic radiation, and said energizing means further comprises:

alternating current means for applying an AC signal to said gas discharge lamp to ionize the gas therein for establishing an electrically conductive path therethrough to generate an electrical arc therein;

first DC means for applying a first DC signal having a magnitude sufficient to sustain said are across said lamp;

second direct current means for applying a second DC signal to said gas discharge lamp for providing a preselected power dissipation therein for sustaining said arc;

third direct current means for supplying a third direct current signal less than said first and said second direct current signals across said gas lamp for providing the required thermal energy for electron emission of said gas discharge lamp for stable operation; and

means for selectively switching between said AC signal means, said first DC signal means, and second DC signal means and said third DC signal means.

6. An improved portable searchlight arrangement comprising, in combination:

a source of electromagnetic radiation having a forward electrode and a rear electrode spaced from said forward electrode for emitting electromagnetic radiation in a preselected distribution, and said emitted electromagnetic radiation having energy in a preselected bandwidth;

reflector means adjacent said source of electromagnetic radiation for receiving a first portion of said electromagnetic radiation in said preselected distribution and reflecting said first portion of said electromagnetic radiation therefrom in a first preselected directional pattern;

mounting means for supporting said source of electromagnetic radiation at preselected positions in spaced apart relationship to said reflector means, and said mounting means comprising:

an electrically conductive forward clip means coupled in electrically conductive contact with said forward electrode of said source of electromagnetic radiation; and

an electrically conductive rear clip means coupled in electrically conductive contact with said rear electrode of said source of electromagnetic radiation; and

at least one of said forward clip means and said rear clip means comprising a spring clip means for sliding, frictional retention of said source of electromagnetic radiation for the condition of movement of said source of electromagnetic radiation in first portions of said preselected positions;

adjustment means on said mounting means for moving said source of electromagnetic radiation into said preselected positions;

shield means adjacent said source of electromagnetic radiation for intercepting a second portion of said electromagnetic radiation in said preselected distribution to prevent said second portion of electromagnetic radiation from emission in a second preselected directional pattern different from said first preselected directional pattern;

shield support means for supporting said shield means for movement with said source of electromagnetic radiation for the condition of movement of said source of electromagnetic radiation in second portions of said preselected positions, and said source of electromagnetic radiation moveable with respect to said shield means for movement of said source of electromagnetic radiation in said first portions of said preselected positions; and energizing means connected to said forward clip means and to said rear clip means for supplying energy to said source of electromagnetic radiation, and comprising: a source of DC electrical energy; an inverter stage means for converting said DC electrical energy to an AC electrical signal having a first predetermined voltage; rectifier means for converting said AC signal to a DC signal having a first DC signal voltage; means for decreasing said first DC voltage to otherDC voltages less than said first DC voltage; and switching means for selectively applying at least said DC signal at said first DC voltage and said other DC signal voltages to said source ofelectromagnetic radiation. 7. The arrangement defined in claim and further comprising:

means for increasing the voltage of said AC electrical signal to a second AC voltage level greater than said first, and said second AC voltage level provides a starting AC voltage to said source of electromagnetic radiation; said switching means further comprises means for selectively applying said second AC voltage to said source of electromagnetic radiation; said rectifier stage comprises a four-diode bridge rectifier; said inverter stage comprises a first transistor and a second transistor and said first transistor and said second transistor having different transistor characteristics. 8. The arrangement defined in claim 6 and further compris- 16 ing:

electrical chopper means and spark gap means for generating a high-voltage, AC signal for starting said source of electromagnetic radiation; and means for selectively applying said high-voltage, AC signal to said source of electromagnetic radiation. 9. The arrangement defined in claim 6 wherein: said energizing means for supplying energy to said source of electromagnetic radiation further comprises: DC electrical energy supply means; electrical chopper and spark gap means operatively connected to said DC electrical energy supply means for generating a high-voltage, AC signal to start said source of electromagnetic radiation; first capacitor means connected to said source of DC electrical energy and to said source of electromagnetic radiation for supplying a short duration high-DC voltage level to said source of electromagnetic radiation; said DC electrical energy source means comprises a first battery means having a first voltage and a second battery means having a second voltage approximately onehalf said first voltage; means for applying a DC signal having a voltage equivalent to the sum of said first battery and said second battery to said source of electromagnetic radiation for providing an intermediate level DC signal; means for applying a DC voltage signal having a voltage equivalent to said first battery to said source of electromagnetic radiation for supplying said low-level DC signal thereto; and means for sequentially and selectively applying said AC signal, said high-level DC signal, said intermediate level DC signal and said low-level DC signal to said source of electromagnetic radiation. 

1. An improved portable searchlight arrangement comprising, in combination: a case means; a source of electromagnetic radiation having a forward electrode and a rear electrode spaced from said forward electrode for emitting electromagnetic radiation in a preselected distribution, and said emitted electromagnetic radiation having energy in a preselected bandwidth; reflector means coupled to said case means for support therein in a predetermined position, and comprising a parabolic reflector means having a predetermined focal point on a preselected axis thereof, and adjacent said source of electromagnetic radiation for receiving a first portion of said electromagnetic radiation in said preselected distribution and reflecting said first portion of said electromagnetic radiation therefrom in a first preselected directional pattern; mounting means for supporting said source of electromagnetic radiation at preselected positions in spaced apart relationship to said reflector means, and said predetermined focal point comprising one of said preselected positions, and said mounting means comprising: an electrically conductive forward spring clip means coupled in Electrically conductive contact with said forward electrode of said source of electromagnetic radiation for sliding, frictional retention of said source of electromagnetic radiation for the condition of movement of said source of electromagnetic radiation in first portions of said preselected positions; and an electrically conductive rear clip means coupled in electrically conductive contact with said rear electrode of said source of electromagnetic radiation; shield means adjacent said source of electromagnetic radiation for intercepting a second portion of said electromagnetic radiation in said preselected distribution to prevent said second portion of electromagnetic radiation from emission in a second preselected directional pattern different from said first preselected directional pattern; adjustment means on said mounting means for moving said source of electromagnetic radiation into said preselected positions, and said adjustment means comprising: axial movement means for selectively moving said source of electromagnetic radiation along said axis relative to said shield means and said reflector means to first axial positions closer to and further from said reflector means and said focal point thereof, and said first axial positions comprise said first portion of said preselected positions; a radial adjustment means coupled to said forward spring clip means and moveably mounted on said case means; electrically insulating means coupled to said rear clip means; and said axial movement means coupled to said electrically insulating means; shield support means for supporting said shield means for movement with said source of electromagnetic radiation for the condition of movement of said source of electromagnetic radiation in second portions of said preselected positions, and said source of electromagnetic radiation moveable with respect to said shield means for movement of said source of electromagnetic radiation in said first portions of said preselected positions; energizing means connected to said forward spring clip means and to said rear clip means for supplying energy to said source of electromagnetic radiation.
 2. The arrangement defined in claim 1 wherein: said electrically insulating means comprises an electrically insulating screw member and said axial movement means comprises a threaded knob mounted on said case means and threadingly engaging said threaded electrically insulating means whereby rotation of said knob moves said electrically insulating means and said source of electromagnetic radiation along the axis of said reflector.
 3. The arrangement defined in claim 1 wherein: said electrically insulating means comprises an electrically insulated bracket member; and said axial movement means comprises a lever means having a pivot end and a movement end and said electrically insulating bracket means is pivotally coupled to said axial movement lever means intermediate said pivot end and said adjustment end, and said pivot end is pivotally mounted on said case means, whereby movement of said adjustment end of said axial adjustment lever moves said source of electromagnetic radiation along said axis of said reflector.
 4. The arrangement defined in claim 1 wherein: said axial adjustment means comprises three strut members extending from said front spring clip means to said case means, a first and a second of said strut members adjustably coupled to said case means and the third strut member spring-mounted on said case means.
 5. An improved portable searchlight arrangement comprising, in combination: a source of electromagnetic radiation comprising a gas discharge lamp means having a forward electrode and a rear electrode spaced from said forward electrode for emitting electromagnetic radiation in a preselected distribution, and said emitted electromagnetic radiation having energy in a preselected bandwidth, and said preselected bandwidth of electromagnetic radiation is iN the visible portion of the electromagnetic radiation spectrum; reflector means adjacent said source of electromagnetic radiation for receiving a first portion of said electromagnetic radiation in said preselected distribution and reflecting said first portion of said electromagnetic radiation therefrom in a first preselected directional pattern; mounting means for supporting said source of electromagnetic radiation at preselected positions in spaced apart relationship to said reflector means, and said mounting means comprising: an electrically conductive forward clip means coupled in electrically conductive contact with said forward electrode of said source of electromagnetic radiation; and an electrically conductive rear clip means coupled in electrically conductive contact with said rear electrode of said source of electromagnetic radiation; and at least one of said forward clip means and said rear clip means comprises a spring clip means for sliding, frictional retention of said source of electromagnetic radiation for the condition of movement of said source of electromagnetic radiation in first portions of said preselected positions; adjustment means on said mounting means for moving said source of electromagnetic radiation into said preselected positions; shield means adjacent said source of electromagnetic radiation for intercepting a second portion of said electromagnetic radiation in said preselected distribution to prevent said second portion of electromagnetic radiation from emission in a second preselected directional pattern different from said first preselected directional pattern; shield support means for supporting said shield means for movement with said source of electromagnetic radiation for the condition of movement of said source of electromagnetic radiation in second portions of said preselected positions and said source of electromagnetic radiation moveable with respect to said shield means for movement of said source of electromagnetic radiation in said first portion of said preselected positions; and energizing means connected to said forward clip means and to said rear clip means for supplying energy to said source of electromagnetic radiation, and said energizing means further comprises: alternating current means for applying an AC signal to said gas discharge lamp to ionize the gas therein for establishing an electrically conductive path therethrough to generate an electrical arc therein; first DC means for applying a first DC signal having a magnitude sufficient to sustain said arc across said lamp; second direct current means for applying a second DC signal to said gas discharge lamp for providing a preselected power dissipation therein for sustaining said arc; third direct current means for supplying a third direct current signal less than said first and said second direct current signals across said gas lamp for providing the required thermal energy for electron emission of said gas discharge lamp for stable operation; and means for selectively switching between said AC signal means, said first DC signal means, and second DC signal means and said third DC signal means.
 6. An improved portable searchlight arrangement comprising, in combination: a source of electromagnetic radiation having a forward electrode and a rear electrode spaced from said forward electrode for emitting electromagnetic radiation in a preselected distribution, and said emitted electromagnetic radiation having energy in a preselected bandwidth; reflector means adjacent said source of electromagnetic radiation for receiving a first portion of said electromagnetic radiation in said preselected distribution and reflecting said first portion of said electromagnetic radiation therefrom in a first preselected directional pattern; mounting means for supporting said source of electromagnetic radiation at preselected positions in spaced apart relationship to said reflector means, and sAid mounting means comprising: an electrically conductive forward clip means coupled in electrically conductive contact with said forward electrode of said source of electromagnetic radiation; and an electrically conductive rear clip means coupled in electrically conductive contact with said rear electrode of said source of electromagnetic radiation; and at least one of said forward clip means and said rear clip means comprising a spring clip means for sliding, frictional retention of said source of electromagnetic radiation for the condition of movement of said source of electromagnetic radiation in first portions of said preselected positions; adjustment means on said mounting means for moving said source of electromagnetic radiation into said preselected positions; shield means adjacent said source of electromagnetic radiation for intercepting a second portion of said electromagnetic radiation in said preselected distribution to prevent said second portion of electromagnetic radiation from emission in a second preselected directional pattern different from said first preselected directional pattern; shield support means for supporting said shield means for movement with said source of electromagnetic radiation for the condition of movement of said source of electromagnetic radiation in second portions of said preselected positions, and said source of electromagnetic radiation moveable with respect to said shield means for movement of said source of electromagnetic radiation in said first portions of said preselected positions; and energizing means connected to said forward clip means and to said rear clip means for supplying energy to said source of electromagnetic radiation, and comprising: a source of DC electrical energy; an inverter stage means for converting said DC electrical energy to an AC electrical signal having a first predetermined voltage; rectifier means for converting said AC signal to a DC signal having a first DC signal voltage; means for decreasing said first DC voltage to other DC voltages less than said first DC voltage; and switching means for selectively applying at least said DC signal at said first DC voltage and said other DC signal voltages to said source of electromagnetic radiation.
 7. The arrangement defined in claim 10 and further comprising: means for increasing the voltage of said AC electrical signal to a second AC voltage level greater than said first, and said second AC voltage level provides a starting AC voltage to said source of electromagnetic radiation; said switching means further comprises means for selectively applying said second AC voltage to said source of electromagnetic radiation; said rectifier stage comprises a four-diode bridge rectifier; said inverter stage comprises a first transistor and a second transistor and said first transistor and said second transistor having different transistor characteristics.
 8. The arrangement defined in claim 6 and further comprising: electrical chopper means and spark gap means for generating a high-voltage, AC signal for starting said source of electromagnetic radiation; and means for selectively applying said high-voltage, AC signal to said source of electromagnetic radiation.
 9. The arrangement defined in claim 6 wherein: said energizing means for supplying energy to said source of electromagnetic radiation further comprises: DC electrical energy supply means; electrical chopper and spark gap means operatively connected to said DC electrical energy supply means for generating a high-voltage, AC signal to start said source of electromagnetic radiation; first capacitor means connected to said source of DC electrical energy and to said source of electromagnetic radiation for supplying a short duration high-DC voltage level to said source of electromagnetic radiation; said DC electrical energy source means comprises a first battery means having a first voltage and a second battery means having a second voltage approximately one-half said first voltage; means for applying a DC signal having a voltage equivalent to the sum of said first battery and said second battery to said source of electromagnetic radiation for providing an intermediate level DC signal; means for applying a DC voltage signal having a voltage equivalent to said first battery to said source of electromagnetic radiation for supplying said low-level DC signal thereto; and means for sequentially and selectively applying said AC signal, said high-level DC signal, said intermediate level DC signal and said low-level DC signal to said source of electromagnetic radiation. 